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M-DPSK Demodulator Baseband - Demodulate DPSK-modulated data

Library

PM, in Digital Baseband sublibrary of Modulation

Description

The M-DPSK Demodulator Baseband block demodulates a signal that was modulated using the M-ary differential phase shift keying method. The input is a baseband representation of the modulated signal. The input and output for this block are discrete-time signals. The input can be either a scalar or a frame-based column vector. The block accepts the input data types single and double.

The M-ary number parameter, M, is the number of possible output symbols that can immediately follow a given output symbol. The block compares the current symbol to the previous symbol. The block's first output is the initial condition of zero (or a group of zeros, if the Output type parameter is set to Bit) because there is no previous symbol.

Binary or Integer Outputs

If the Output type parameter is set to Integer, then the block demodulates a phase difference of

θ + 2πk/M

to k, where θ is the Phase rotation parameter and k is an integer between 0 and M-1.

If the Output type parameter is set to Bit and the M-ary number parameter has the form 2^K for some positive integer K, then the block outputs binary representations of integers between 0 and M-1. It outputs a group of K bits, called a binary word, for each symbol.

In binary output mode, the Constellation ordering parameter indicates how the block maps an integer to a corresponding group of K output bits. See the reference pages for theM-DPSK Modulator Baseband andM-PSK Modulator Baseband blocks for details.

Dialog Box

M-ary number

The number of possible modulated symbols that can immediately follow a given symbol.

Output type

Determines whether the output consists of integers or groups of bits.

Constellation ordering

Determines how the block maps each integer to a group of output bits.

Phase rotation (rad)

The phase difference between the previous and current modulated symbols when the input is zero.

Output data type

When the parameter is set to 'Inherit via internal rule' (default setting), the block will inherit the output data type from the input port. The output data type will be the same as the input data type if the input is of type single or double.

For integer outputs, this block can output the data types int8, uint8, int16, uint16, int32, uint32, single, and double. For bit outputs, output can be int8, uint8, int16, uint16, int32, uint32, boolean, single, or double.

Pair Block

M-DPSK Modulator Baseband

References

[1] Pawula, R. F., "On M-ary DPSK Transmission Over Terrestrial and Satellite Channels," IEEE Transactions on Communications, Vol. COM-32, July 1984, 752-761.